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Post by maggotbreath on Jul 18, 2013 22:00:04 GMT
So this coming winter I'll be making a new header, the old one is 1 1/2 inches. Wondering what every one else is using and if going to 1 3/8s will give better spool without reducing the top end?
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Post by nitro on Jul 19, 2013 15:00:19 GMT
I made 35 x 1,5mm on my B12. 35mm as compromise between optic and spool up time and 1,5mm thickness because of weight. On my dragbike I made 38 x 2mm because of turbo charger weights a lot and because of flowrate.
Proboost has 33 x 2mm for street use if I remember right and for street I guess it´s best. I read a report of someone how made some checks and he made 19mm id header without significant hp losses. Friend of mine has also 33 x 2mm and TD04HL-16T on CBR 1000 with very good results. The next turbo bike for street (if it´s not Hayabusa) I would make same size.
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Post by maggotbreath on Jul 19, 2013 17:43:01 GMT
Good info Nitro, I'm leaning towards the smaller diamiters. I think 1.5 inch (38mm) is on the large size of the equation. Was at a reagonal drag meet last year, couple of the promod Turbo bikes had what looked like 1.5" headers, got me thinking. Also had a look at Uncle Bob's again, seems to back up what you're saying. www.unclebobsturbos.com/newbie.htmlGoing to make a jig for the header, so can always go larger/smaller without tearing the beast apart for fitting. Thinking data logging; exhaust, pre and post intercool pressures. Could be just dreaming though. |
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Post by katana on Jul 19, 2013 18:25:45 GMT
I think 1 3/8" is more than adequate up to 400-450hp exhaust flow. 500+hp and the 1 1/2" will do better. Some of Big CC's Busa and GSXR manifolds are works of art - strong and compact, mainly 2mm 316 stainless.
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Post by pasis on Jul 21, 2013 8:22:39 GMT
We use 38х1.5 mm
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Post by arttu on Jul 21, 2013 8:46:22 GMT
My header has 28mm inner diameter. This is quite popular size and apparently it can flow enough for +400hp without significant restriction. Smaller diameter should produce better spool up and apparently it doesn't hurt top end easily. One very experienced turbo guru told me that he has never managed to use too small tube for headers but opposite has happened few times  On the other hand on all-out race engines larger tube size may help to squeeze out few extra ponies at top end. But for street bike I would use relatively small size. |
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Post by maggotbreath on Jul 22, 2013 15:08:01 GMT
Good info guy's. Looks like I'll go with the smaller tube, thank you very much!
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greybush
Velociraptor
Posts: 27 
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Post by greybush on Jul 24, 2013 20:56:47 GMT
I'm using 1.5 inch od with .065 wall on my bandit. It seems to work great for my application. garrett gt22 on a street bike set at 15lbs boost.
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Teresa O.
Velociraptor
Posts: 37
Bikes: Trickframed 1127, Turbo 14 and many more
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Post by Teresa O. on Jul 25, 2013 5:44:44 GMT
35 X 1,5mm on the last 3 projects... seems to work fine with small turbos though (k04)
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gsnutter
Velociraptor
Posts: 27
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Post by gsnutter on Jul 25, 2013 7:47:28 GMT
Does anyone now where I can buy top hat spacers to weld to the end of the exhaust to have something to bolt up to the head or am I going to have to get on the lathe?
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Post by katana on Jul 25, 2013 18:22:35 GMT
Does anyone now where I can buy top hat spacers to weld to the end of the exhaust to have something to bolt up to the head or am I going to have to get on the lathe? or try and find some 1/8" thick pipe with internal diameter close to header tube outer - cut some 1.5" lengths, add flanges to header tubes then sleeve and weld? |
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On the other hand on all-out race engines larger tube size may help to squeeze out few extra ponies at top end. But for street bike I would use relatively small size.